1. Field of the Invention
This invention relates to devices to regulate movement of a machine part and more particularly to a motion retarder having a surface prepared to frictionally engage the machine part and regulate part movement whether that movement be linear, rotational or both.
2. Prior Art
Use of friction to regulate movement has been known and widely used for many years. For example, an automotive vehicle first uses static friction between its tires and a surface of a road to effect vehicle movement. Once there is movement kinetic friction allows the vehicle to accelerate to a selected rate of travel. Friction is again used to decelerate the vehicle. Braking used to effect deceleration typically includes engagement of a friction member with a brake drum where the kinetic energy from deceleration of the vehicle mass is converted into heat.
Friction also is used by motion retarding devices to regulate other forms of movement. For example, a motion retarder may be used to restrict unwanted lost motion inherent between mechanically linked parts. Additionally, a motion retarder may be used to control positioning of a machine part where externally applied forces may be sufficient in magnitude to effect an unwanted movement of that part. Further uses may include tension control to provide self-adjustment to compensate for wear between joined parts.